@dorianc.b no, you are not forced to use clojurescript it's client side, you can use whatever you prefer what I did: - clojure for the server, to learn the language - javascript on the client to check that my server works as I want it to - now clojurescript on the client

when you see how powerful clojurescript and its ecosystem are, I guess you'll move to clojurescript as well 🙂

what regex can capture the word surrounded by another word (from either sides)... like: #"house (\w+) | (\w+) house"

maybe there is a more elegant way of writing it

@dimovich Maybe something like this:

(\w+)?house(\w+)?

I’m trying to write an algorithm for modified competition ranking (https://en.wikipedia.org/wiki/Ranking#Modified_competition_ranking_.28.221334.22_ranking.29) in clojure, but I’m not making any headway into something that would be elegant. How could I prevent lookups into previous map values?

Anyone ever done anything similar to this?

Standard ranking is trivial (map-indexed (fn [idx itm] (conj itm {:rank (+ idx 1)})) leaderboard))

I would have done this in five minutes in Java

@fatihict yeah, thanks!

@singen So you have this code?

Yep

I think you might want a reducer here really. Because you need to "look back" as you build up, to check for equivalents.

Exactly

I’ve been scratching my head over how to map with previous value

Check out reduce I think 🙂

But I can’t find any examples that are enough alike

Alternatively, start with the map-indexed and massage it after

It won’t work, because you need the result of the previous iteration

Reduce looks like it might do what I want, but all the examples I find are extremely dissimilar to what I want to do. I can’t figure out the syntax, really.

It's a little hard to explain, essentially you have an "accumulator" and a "new item"

And each time the fn is called (with accumulator, and the next item from the list), you return a new value for the accumulator

Could you, for example make map-indexed with reduce?

Probably, yeah

I think you can build most things with reduce actually

Just putting together a related example for you 🙂

Oh, thanks!

(reduce
  (fn [ld itm]
    (let [last-item (last ld)
          last-value (first last-item)
          last-rank (:rank (last last-item))]
      (if (= itm last-value)
        (conj ld [itm {:rank last-rank}])
        (conj ld [itm {:rank (inc (count ld))}]))))
  []
  [1 2 2 4])

That does standard competition ranking. Doing modified ranking is a little more complex, plus I'll steal all the fun if I solve it for you 😉.

That looks like it will help, a lot

Thanks!

Modified ranking is slightly harder to implement, but not too difficult. There is probably a better way to do this, but reduce is what comes to mind. I'm sure someone will weight in with a one-liner at some point.

No problem!

Ask again if you need further help

I’m pretty much in the beginning of my clojure learning and I’m learning about maps but I got this error. Is conj not applicable to maps?(conj {:b 2,:a 1} :c 3) IllegalArgumentException Don't know how to create ISeq from: clojure.lang.Keyword clojure.lang.RT.seqFrom (RT.java:542)

(conj {:b 2,:a 1} {:c 3})

Does that answer your question? 🙂

Yea just figured it out after I asked lol. Not much syntax but it’s a taking a bit to sink in

@dominicm I just figured out how reduce works and solved my problem 🙂

@dorianc.b The most common way to do it is to use assoc, though: (assoc {:b 2 :a 1} :c 3)

thanks ill keep that in mind. I’m currently just going through the Clojure the brave book so I just started

App won’t build on heroku, need help quick:

-----> SSH app detected
-----> Installing ngrok...  !     Push rejected, failed to compile SSH app.
 !     Push failed